Roll changing device



May 31, 1960 M. LANGEN ROLL CHANGING DEVICE 4 Sheets-Sheet l Filed July8, 1954 ATTORNEYS lgs/VENTOR Mcnhlos Lungen M, LANGEN ROLL CHANGIN May31, 1960 G DEVICE 4 Sheets-Sheet 2 Filed July 8, 1954 VVV VVV fr /r v ONATTORNEYS M. LANGEN ROLL CHANGIN May 31, 1960 G DEVICE 4 Sheets-Sheet 3Filed July 8. 1954 ATTORNEYS M. LANGEN ROLL CHANGING May 31, 1960 DEVICE4 Sheets-Sheet 4 Filed July 8. 1954 H vz/E/vroR Mo'rhlas LungenATTORNEYS RLL CHANGING DEVICE Mathias Langen, Parkstone, Dorset,England, assignor to The Loewy Engineering Company Limited, Loudon,England, a corporation of Great Britain Filed July 8, 1954, Ser. No.442,041

Claims priority, application Great Britain July 9, 1953 2 Claims. (Cl.254-106) This invention relates to a roll changing device for a rollingmill and, in particular, to a roll changing device in which the rollsare inserted into the mill stand or withdrawn therefrom by being movedsideways with respect to the mill stand.

Roll changing devices of this type are particularly useful in connectionwith rolling mills in which the separating forces are considerable, suchas four-high mills, and where, consequently, large screwdown gears arerequired, as the sideways movement of the rolls makes it possible forthe rolling mill housings to have closed tops, whereby their strengthand rigidity are greatly improved, particularly in that part whichaccommodates the Screwdown gear.

A roll changing device of the type above referred to comprises generallya movable support or carrier in the form of a Sledge receiving therolls, together with any attachments, Such as their bearings or chocks,the sledge being adapted to be moved sideways with respect to therolling mill Stand along a track to a point outside and adjacent themill stand where the rolls can be taken oi the Sledge and replaced byanother roll assembly.

The weight of a roll assembly to be carried by the sledge is often veryheavy, and the forces required for moving the Sledge with a rollassembly loaded thereon are therefore considerable.

Various proposals have been made in the past for displacing the Sledgeof a roll changing device sideways into and out of a rolling mill stand.None of these was, however, quite satisfactory.

Movement of the Sledge by ropes connected to'the lifting tackle of atravelling crane lacked precise control, a disadvantage which wasparticularly apparent when moving the rolls into position inside themill Stand. The use of ropes necessitated also the arrangement ofpulleys at both sides of the mill stand. This was inconvenient becausespace at least on one side of the mill is always restricted by therolling mill drive.

It has further been proposed to provide a roll changing device withshifting means, permanently connected to the Sledge, whereby a moreprecise control of its movement is achieved.

These means consisted either of a nut traversing a threaded spindle, orof a hydraulic cylinder with a double-acting piston displaceabletherein. The length of the spindle and that of the cylinder weredetermined by the distance between the two extreme positions of theSledge. If this distance was great, as in the case of mills having rollsof great barrel length, the spindle and the cylinder became Veryexpensive and cumbersome. Building up a long cylinder from a number ofshells joined endwise together was found to be inexpedient for variousreasons.

It is an object of the present invention to provide a roll changingdevice for rolling mill stands comprising a movable support or a carrierin the form of a Sledge,

States Patent C rerice having improved means for Shifting said sledge inor out of the rolling mill stand.

The shifting means according to the invention are of the hydraulic typeand they comprise accordingly a pres- Sure-fluid cylinder and adouble-acting piston. Of these two elements, one is connected directlyto the Sledge, while the other canslide along a track and be immobilizedat spaced-apart and pre-selected points 'on that track. The track forthe slidable 'element may be the same as that for the sledge.

The element 'connected to the Sledge is preferably formed by thedouble-acting piston, and the slidable element formed by the cylinder,although the arrangement can be reversed. Displacement of the piston inthe cylinder, with the cylinder locked to the track, will result in acorresponding displacement of the Sledge along its track. Displacementof the piston in the cylinder, with the cylinder free to slide along thetrack and the sledge loaded with a set of rolls, will result in -acorresponding displacement of' the cylinder along the track, as thepiston and the Sledge will be immobilized by the weight of the rolls onthe Sledge. In this way, the cylinder can be moved towards or away fromthe mill stand by a distance equal to the stroke of the piston.

This arrangement and mode of operation permits the movement of theSledge along its track by a total distance which is a multiple of thestroke of the piston relative to the cylinder, simply by alternatelyadmitting pressure-fluid to opposite sides of the piston and freeing orlocking the cylinder to the track at alternate Strokes of the piston.

It will be realised that, in this way, the length of the stroke of thepiston, and accordingly the length of the cylinder required for movingthe sledge in or out of the mill Stand by a given distance, can begreatly reduced and need only be a fraction of the stroke which wouldotherwise be required to move the Sledge by the same distance. TheShifting means according to the invention are therefore comparativelysimple and inexpensive and do not require excessive space for theiraccommodation adjacent the rolling mill stand.

According to a further feature of the invention, control means areprovided for alternately admitting pressure-duid to opposite Sides ofthe double-acting cylinder.

Locking means may be provided for immobilizing the slidable elements atspaced-apart and pre-selected points along its track. These lockingmeans may be in the form of pivoted pawls engageable in notches providedat spacedapart and pre-selected points along the track.

The invention will now be described by way of example with reference tothe accompanying drawings, which show one embodiment of the invention:

Fig. 1 is a front elevation showing a roll changing device according tothe invention applied to a four-high rolling mill, with its hydraulicshifting means in section.

Figs. 2, 3, 4, 5 and 6 show, on a somewhat larger scale, variouspositions which the hydraulic Shifting means take up during a movementaway from and towards the rolling mill stand.

Fig. 7 is a plan view of the roll changing device of Fig. 1.

Fig. 8 is a cross-section through the hydraulic shifting means accordingto line 8 8 of Fig. l.

Fig. 9 is a cross-section through the hydraulic shifting means accordingto line 9--9 of Fig. 1.

Referring to Fig. 1, the rolling mill, to which the roll changing deviceaccording to the invention is applied, is generally designated with 10.It is shown here as a fourhigh mill comprising work rolls 11, 12 andback-up rolls 13, 14. The chocks for the four rolls 11 to 14 are notseparately shown as they are immaterial for the 'present first pull-outmovement of the sledge 20.

invention; -they areV-locatedvwithin the spaces 15 and 16 at both sidesof the rolls. The four rolls and their chocks form together the rollassembly 17 and will be referred to as such in the followingdescription.

The roll' changing device comprises a sledge 20 which ,is adapted toreceive the roll assembly 17 and which can be moved together with a rollassembly into and sideways out of the rolling mill stand 10. The sledge20 is movable along a track 21 by hydraulic shiftingV means generallydesignated-by 22. These means comprise a cylinder element 23 and adouble-acting piston element 24. The piston has a piston rod 25 which,at its end, carries a hook 26 adapted to enter a notch 27 in the sledge20. The cylinder 23 is displaceable along the same track as the sledge20, and its base-plate 28 is provided to this end with shoes 29vslidable along the track V21 (Fig. 9).

- Attached to the cylinder 23, at both of its sides, are double-actingpawls 30 which can swing in opposite directions about pins 31 formed oncylinder bosses 32 (Fig. 8). These pawls co-operate with notches 33arranged on the track 21 at stations A, B and C which are spaced-apartby a distance equal to the stroke length of the piston 24. AtV each ofthese three stations there are on each side of the track two notches 33which form together dovetails 34 on the track 21. The notches 33 on themill stand side of the dove-tail 34 are engaged by the pawls 30 duringthe inward travel of the Sledge and the notches at the opposite side ofthe dove-tail at the outward travel of the Sledge. Each pawl 30 hasaccordingly two lugs with inclined faces 35 which can be alternatelymade to engage` one of the two notches 33 at opposite sides of adove-tail 34 by tilting a pawl 30 about its pivot pin 31. Tilting of thepawls 30 is effected by means of weighted rocking arms 36 attached tothepawls.V The transition from a notch 33 to the upper level of the track21 is formed by a slope 37 which acts as a cam-face for tilting a pawlon its becomingdisengaged from a notch, so that Ythe pawl can ride andpressure-fluid is, therefore, admitted to the right of the piston 24,whilst the pressure-fluid on the leftof the piston is exhausted. Thisresults in a movement of the cylinder 23 to the right, i.e., away fromthe mill stand 10, with the piston 24 remaining stationary, as theweight of the roll assembly carried by sledge 20 is much in excess ofthat of the cylinder 23 and immobilizes the sledge and the piston.During this movement, the pawls 30 ride over the slopes 37 of thenotches 33 whereby the pawls are tilted slightly. The stroke of thecylinder 23 during this step has the same length as that.of the piston24 during the iirst pull-out movement, the cylinder 23 occupying at theend of its stroke theposition shown in Fig. 3vwith the pawls 30 engagingthe notches at station B, whereby they immobilize the cylinder in itsnew position.

The hydraulicY shifting device 22 is now ready for another stroke of thepiston 24. This is effected by reversing again the connections of thehydraulic cylinder 23 by means of the hydraulic control valve 44,pressureiiuid being admitted to the left of the piston 24 yand exhaustedfrom the right, in the same way as during the iirst step. The piston,together With the sledge 20, is thereby moved Yaway'from the mill stand10 by another stroke length, its position at the end of the stroke andthat of the Sledge hook 26 beingV indicated in dotted lines in lig. 3.This is the second pull-out movement.

The hydraulic pressure-huid connections are thereupon again reversed bymeans of the control valve 44 which results in the displacement of thecylinder, 23 along the track 21 whilst the sledge 20 remains stationaryowing to the weight of the roll assembly 17 (Fig. 4).

. The cylinder 23 moves until the pawls 30 enter the freely along thetrack'21 until it drops'into the next notch 33. Hydraulic pressure-fluidis supplied to the cylinder 23 by means of flexible hoses 38, 39 whichare connected at their ends to lixed pipes 40, 41 and 42, 43respectively. The `admission of pressure-huid to the cylinder 23 iscontrolled by a hand-operated valve 44, or any other suitable means.Y Apump, not shown here, is provided as a source of supplyofpressure-fluid. f Y

' 4T'he stops 45 and 46 at opposite ends of the track-21`preventover-travel of the shifting means 22 in vboth VVdirections.Stops 45, 46 co-operate with ears 47 protruding from the four corners ofthe base-plate'28. Y

The track 21 for the shifting means 22 is preferably located in a pitbelow iloor level, a second somewhat deeper pit being provided alongsidethe track for accommodating the loops formed by the flexible hoses 38and 39 (Figs.

o sand9),

(The operation of the hydraulic shifting means 22 will now be-describedin detail with reference Ytothe Figs. 2,

3, 4,V 5 and V6: Before the removal of a Vroll assembly 17 from the millstand 10, the parts have the positions shown inFig. 2,

witlrthe hydraulic cylinder 23 being immobilized on the Y track V21through the pawls 30 engaging the'notches 33 wat A. In this position,the ears 47 are close to the stops 45 on the track 21, although not inactual contact with them.

Pressure-fluid is now admitted to the left of piston 24, whereby thelatter is moved towards the right. This kcauses the sledge 20, with aroll assembly 17, to be pulled out of the rolling mill stand 10 by'adistance corresponding Vto the stroke of the piston. The positions ofthe piston 24 at the end of the stroke and of the sledge hook 26 Vareindicated inl dotted lines in Fig. 2. This step forms the The Vcontrolvalve 44 is now operated .so as to reverse Vthe pressure andexhaust-connections to the cylinder 23 notches 33 at station C. In thisposition, the 'ears 47 at the right-hand end of the base-plate 28 arevery close to thestops 46, although not in actual engagement with them.

This is followed by a further reversal of the pressure- Vfluidconnections, resulting in a displacement of the piston 24 along thetrack 21 whilst the cylinder 23 is immobilized through the pawls 30having entered the notches at station C. This forms the third pull-outmovement. The Sledge 20V is now in a position in which the roll assembly17 can be'lifted therefrom and'replaced by another rollas'sembly whichis to take the place of the iirstY one in the mill stand 10. v

For. the return movement of the Sledge 20, pressurefluid is admittedtothe right-hand side of piston 24. VVThis will cause the cylinder 23 tomovev a short distance to the right until the ears 47 and-the stops 46are in engage- -mentwith each other (Fig. 5), whereby the pawls 30 arecaused to become disengaged from their notches 33 at C. The pawls 30 canthen be swung about their Y pivot pins 31 by Vmeans oftheactuatinglevers 36,'as

soV

,arrangement of the shifting means.

together with the sledge 20, to move to the left. Fig. 5

shows the piston 24 and the sledge 20 in their positions at the end oflthis stroke. This completes the lirst pushback movement. Y

The cylinder 23 is now moved towards the mill stand 10 by reversing theposition of the controlvalve 44, with the sledge being immobilized`owing .to the weight of the roll assembly. The cylinder travels backuntil its pawls 30 enter the notches 33 at B. The alternate movements ofpiston 24 and cylinder 23 are-repeated, as indicatedin Fig. 6, until thecylinder has reached the position in which its pawls 30 enter thenotches 33'at A, and until the sledge 20 is inside the rolling millstand 10.

It will be seen that the entire stroke of the Sledge 20 between its twoextreme positions is carried out in three steps. This Yresults inreducing the stroke requiredfrom the piston and, thereby, also thelength of the cylinder, by two-thirds, with a consequent simplicatloninthe It is preferred to move the cylinder 23V at a higher the variabledelivery type is very Well suited to these conditions as this type ofpump gives a high output at slow speeds, and a small output at highspeeds.

of shifting means having a The invention is capable of embodiments otherthan those shown here. The operation of the shifting means can be madeautomatic by providing electric limit switches alongside the track whichactuate the hydraulic control valve for the pressure-duid if and vwhenthe cylinder and What I claim is:

1. In combination, a horizontal track and self-propelled shifting meanscarried by said track for shifting a load along said track, saidshifting means comprising a double comparatively short stroke.'

ment of said load, and said latching means when moved to said uponadmission of pressure fluid to one of the sides of

